Initially really liked this plugin, until I noticed one week too late that it was blocking googlebots and had destroyed my keyword rankings. My traffic is now 1/4 of what it used to be. Googlebots are crawling again after I removed the plugin, but hard to say how long it will take to regain traffic. Other similar complaints:

Also multiple readers alerted me that they were being automatically logged in to one of my admin accounts after I installed this. Could be a very useful plugin but unfortunately has a dangerous downside and should be avoided.